Control panels having backlit buttons are known for use in the interior of automotive vehicles, including radio control buttons and door lock buttons. The purpose of backlit buttons is to allow a user to see the button and its function even in low light situations. Typically, a radio button will have a graphic image or other indicia to indicate a particular purpose. For example, the word “scan” or a number such as “3” is provided on a button to indicate that button's purpose. One known button is made by injection molding a clear plastic material in the form of a button. The button is then painted with a layer of white paint and dried by an oven or other conventional technique. Next, a layer of black paint is applied over the white paint and is subsequently dried. A laser is used to etch away a desired portion of the black paint to form a white graphic image. In a low light situation, the button is illuminated from behind such that the graphic image is visible to a user through the white paint layer.
Another known method of making buttons for a control panel involves providing a transparent member with a black layer on one side and vacuum forming the transparent member with the black layer into a desired shape. Thereafter, a laser passes through the transparent member and etches away a desired portion of the black layer to form a graphic image. Next, a daytime color is pad printed over the black layer side and dried in an oven followed by pad printing a nighttime color on top of the daytime color and oven drying the nighttime color. Finally, the subassembly is placed in an injection molding apparatus and an interior recess of the button is filled with resin during injection molding to make the button more rigid.
It is further known to provide control panels having backlit buttons on a switch pad for resilient switching action. However, the known buttons have a generally flat upper surface to be sure that light can fully reach and evenly illuminate a graphic image on the button. In addition, the graphic image may be partially blocked from illuminating light by part of the switch mat because of the way the button rests on the switch mat. Thus, the graphic image will not be fully visible when backlit.